PPTX files in this directory are made by hand using PowerPoint. This most faithfully represents source files likely to be used by users of this library. Files produced by `python-pptx` are "cleaner" in certain respects and may pass tests that a "real" PowerPoint file would not.

We may also wish to add files made with LibreOffice since the XML it generates, while consistent with the ISO 29500 spec, can differ enough from that generated by Microsoft PowerPoint to produce different results on certain tests.
